The present invention relates to an anti-submarine device installed to the seat frame of an automobile seat for preventing the submarine phenomenon from acting on a seat occupant in sudden stops, such as head-on collisions.
In a head-on collision or other sudden stop, passengers wearing a seatbelt in the front seat may experience their buttocks being thrown forward and pushed below the seat cushion by inertial force. This situation is referred to as a xe2x80x9csubmarine phenomenon.xe2x80x9d The submarine phenomenon sometimes causes a seatbelt to compress the upper abdominal region of the passenger with the danger of a visceral rupture.
Considering the above-described danger, a conventional seat structure for a vehicle, as shown in FIG. 4, is provided with a seat frame 100 having an incline 200 adjacent to the front end thereof for preventing the submarine phenomenon. The conventional seat structure, however, is disadvantageous in that an additional process is required to attach the incline 200 to the seat frame 100. Also, this type of anti-submarine is not efficient because the incline 200 is usually made of a foam material, such as a polyurethane having a resilient property, and the protrusion of the seat cushion at incline 200 can cause passenger discomfort along the thighs.
Consequently, a seat assembly according to the prior art is not able to meet the requirements of improved in comfort and anti-submarine function at the same time.
The present invention provides an anti-submarine device, which enables the front end of a seat cushion to be placed downward such that passengers, including a driver, feel comfortable when an automobile is driving normally, and which enables the front end of the seat cushion to upwardly protrude so as to rigidly hold the buttocks of the passenger during a head-on collision or sudden stop. Accordingly, it is possible to provide an anti-submarine device of a seat for an automobile capable of simultaneously addressing the comfort of the seat and function to prevent the submarine phenomenon.
In a preferred embodiment of the present invention, such as anti-submarine device comprises a submarine bar, push links, a stopper, a push panel and a torsion spring. The submarine bar has one side edge pivotally connected to a first pivotal shaft in order to permit upward rotation through an opening formed on a seat frame. The downwardly curved push links have an end rotatably fixed to the both sides of the submarine bar by means of pins. The stopper is inserted into guide slots formed at the ends of the push links. The slots have a certain length, which limits the operation of the push links within a predetermined range. The push panel is integrally formed with the opposite ends of the push links. The panel is capable of rotating around a second pivotal shaft by the load of femoral region of the passenger during a head-on collision or other sudden stop. The torsion spring is installed on the second pivotal shaft in order to return the push panel to the original state when the load applied to the push panel is released.
In an alternative preferred embodiment of the invention, an automobile seat including an anti-submarine device comprises a seat frame defining an opening with a prism shaped member disposed therein. A first pivot shaft is disposed along a front edge of the opening. The prism shaped member is pivoted on the pivot shaft along one edge or apex of the prism. A second pivot shaft is mounted on the seat frame behind the opening. A push panel pivotably mounted on the second pivot shaft is positioned in the seat frame to be depressed by load from a seat occupant in a sudden stop condition. A linkage is provided between the push panel and prism shaped member such that depression of the push panel raises the prism shaped member to prevent submarining of a seat occupant during a sudden stop. The prism shaped member may be referred to as a submarine bar.
Preferably the linkage comprises push links and a stopper bar. First and second push links are disposed at opposite ends of the push panel and linked to opposite ends of the prism shaped member. The push links are non-rotatably fixed to the push panel and rotatably attached to the prism shaped member. Each push link also defines a longitudinally running guide slot adjacent the prism shaped member. The stopper bar is slidably received in the guide slots to limit movement of the linkage through a predetermined range. At least one torsion spring is preferably mounted on the second pivot shaft acting on the push panel to return the push panel after depression.